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<a name="gst-plugins-good-plugins-audioiirfilter"></a><div class="titlepage"></div>
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<h2><span class="refentrytitle"><a name="gst-plugins-good-plugins-audioiirfilter.top_of_page"></a>audioiirfilter</span></h2>
<p>audioiirfilter</p>
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<td class="gallery_image" valign="top" align="right"></td>
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<div class="refsect1">
<a name="gst-plugins-good-plugins-audioiirfilter.properties"></a><h2>Properties</h2>
<div class="informaltable"><table class="informaltable" border="0">
<colgroup>
<col width="150px" class="properties_type">
<col width="300px" class="properties_name">
<col width="200px" class="properties_flags">
</colgroup>
<tbody>
<tr>
<td class="property_type">
<a href="/usr/share/gtk-doc/html/gobject/gobject-Value-arrays.html#GValueArray-struct"><span class="type">GValueArray</span></a> *</td>
<td class="property_name"><a class="link" href="gst-plugins-good-plugins-audioiirfilter.html#GstAudioIIRFilter--a" title="The “a” property">a</a></td>
<td class="property_flags">Read / Write</td>
</tr>
<tr>
<td class="property_type">
<a href="/usr/share/gtk-doc/html/gobject/gobject-Value-arrays.html#GValueArray-struct"><span class="type">GValueArray</span></a> *</td>
<td class="property_name"><a class="link" href="gst-plugins-good-plugins-audioiirfilter.html#GstAudioIIRFilter--b" title="The “b” property">b</a></td>
<td class="property_flags">Read / Write</td>
</tr>
</tbody>
</table></div>
</div>
<div class="refsect1">
<a name="gst-plugins-good-plugins-audioiirfilter.signals"></a><h2>Signals</h2>
<div class="informaltable"><table class="informaltable" border="0">
<colgroup>
<col width="150px" class="signals_return">
<col width="300px" class="signals_name">
<col width="200px" class="signals_flags">
</colgroup>
<tbody><tr>
<td class="signal_type"><span class="returnvalue">void</span></td>
<td class="signal_name"><a class="link" href="gst-plugins-good-plugins-audioiirfilter.html#GstAudioIIRFilter-rate-changed" title="The “rate-changed” signal">rate-changed</a></td>
<td class="signal_flags"><a href="/usr/share/gtk-doc/html/gobject/gobject-Signals.html#G-SIGNAL-RUN-LAST:CAPS">Run Last</a></td>
</tr></tbody>
</table></div>
</div>
<a name="GstAudioIIRFilter"></a><div class="refsect1">
<a name="gst-plugins-good-plugins-audioiirfilter.other"></a><h2>Types and Values</h2>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="name">
<col class="description">
</colgroup>
<tbody><tr>
<td class="datatype_keyword">struct</td>
<td class="function_name"><a class="link" href="gst-plugins-good-plugins-audioiirfilter.html#GstAudioIIRFilter-struct" title="struct GstAudioIIRFilter">GstAudioIIRFilter</a></td>
</tr></tbody>
</table></div>
</div>
<div class="refsect1">
<a name="gst-plugins-good-plugins-audioiirfilter.object-hierarchy"></a><h2>Object Hierarchy</h2>
<pre class="screen">    <a href="/usr/share/gtk-doc/html/gobject/gobject-The-Base-Object-Type.html#GObject-struct">GObject</a>
    <span class="lineart">╰──</span> <a href="/usr/share/gtk-doc/html/gobject/gobject-The-Base-Object-Type.html#GInitiallyUnowned">GInitiallyUnowned</a>
        <span class="lineart">╰──</span> <a href="/usr/share/gtk-doc/html/gstreamer-1.0/GstObject.html#GstObject-struct">GstObject</a>
            <span class="lineart">╰──</span> <a href="/usr/share/gtk-doc/html/gstreamer-1.0/GstElement.html#GstElement-struct">GstElement</a>
                <span class="lineart">╰──</span> <a href="/usr/share/gtk-doc/html/gstreamer-libs-1.0/GstBaseTransform.html#GstBaseTransform-struct">GstBaseTransform</a>
                    <span class="lineart">╰──</span> <a href="/usr/share/gtk-doc/html/gst-plugins-base-libs-1.0/GstAudioFilter.html#GstAudioFilter-struct">GstAudioFilter</a>
                        <span class="lineart">╰──</span> GstAudioFXBaseIIRFilter
                            <span class="lineart">╰──</span> GstAudioIIRFilter
</pre>
</div>
<div class="refsect1">
<a name="gst-plugins-good-plugins-audioiirfilter.description"></a><h2>Description</h2>
<p>audioiirfilter implements a generic audio <a class="ulink" href="http://en.wikipedia.org/wiki/Infinite_impulse_response" target="_top">IIR filter</a>. Before usage the
"a" and "b" properties have to be set to the filter coefficients that
should be used.</p>
<p>The filter coefficients describe the numerator and denominator of the
transfer function.</p>
<p>To change the filter coefficients whenever the sampling rate changes the
"rate-changed" signal can be used. This should be done for most
IIR filters as they're depending on the sampling rate.</p>
<div class="refsect2">
<a name="id-1.2.22.8.5"></a><h3>Example application</h3>
<div class="informalexample">
  <table class="listing_frame" border="0" cellpadding="0" cellspacing="0">
    <tbody>
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        <td class="listing_code"><pre class="programlisting"><span class="comment">/* GStreamer</span>
<span class="comment"> * Copyright (C) 2009 Sebastian Droege &lt;sebastian.droege&#64;collabora.co.uk&gt;</span>
<span class="comment"> *</span>
<span class="comment"> * This library is free software; you can redistribute it and/or</span>
<span class="comment"> * modify it under the terms of the GNU Library General Public</span>
<span class="comment"> * License as published by the Free Software Foundation; either</span>
<span class="comment"> * version 2 of the License, or (at your option) any later version.</span>
<span class="comment"> *</span>
<span class="comment"> * This library is distributed in the hope that it will be useful,</span>
<span class="comment"> * but WITHOUT ANY WARRANTY; without even the implied warranty of</span>
<span class="comment"> * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU</span>
<span class="comment"> * Library General Public License for more details.</span>
<span class="comment"> *</span>
<span class="comment"> * You should have received a copy of the GNU Library General Public</span>
<span class="comment"> * License along with this library; if not, write to the</span>
<span class="comment"> * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,</span>
<span class="comment"> * Boston, MA 02110-1301, USA.</span>
<span class="comment"> */</span>

<span class="comment">/* This small sample application creates a lowpass IIR filter</span>
<span class="comment"> * and applies it to white noise.</span>
<span class="comment"> * See http://www.dspguide.com/ch19/2.htm for a description</span>
<span class="comment"> * of the IIR filter that is used.</span>
<span class="comment"> */</span>

<span class="comment">/* FIXME 0.11: suppress warnings for deprecated API such as GValueArray</span>
<span class="comment"> * with newer GLib versions (&gt;= 2.31.0) */</span>
<span class="gtkdoc ppc">#define GLIB_DISABLE_DEPRECATION_WARNINGS</span>

<span class="gtkdoc ppc">#include &lt;string.h&gt;</span>
<span class="gtkdoc ppc">#include &lt;math.h&gt;</span>

<span class="gtkdoc ppc">#include &lt;gst/gst.h&gt;</span>

<span class="comment">/* Cutoff of 4000 Hz */</span>
<span class="gtkdoc ppc">#define CUTOFF (4000.0)</span>

<span class="gtkdoc kwb">static</span> gboolean
<span class="function">on_message</span> <span class="gtkdoc opt">(</span>GstBus <span class="gtkdoc opt">*</span> bus<span class="gtkdoc opt">,</span> GstMessage <span class="gtkdoc opt">*</span> message<span class="gtkdoc opt">,</span> gpointer user_data<span class="gtkdoc opt">)</span>
<span class="gtkdoc opt">{</span>
  GMainLoop <span class="gtkdoc opt">*</span>loop <span class="gtkdoc opt">= (</span>GMainLoop <span class="gtkdoc opt">*)</span> user_data<span class="gtkdoc opt">;</span>

  <span class="keyword">switch</span> <span class="gtkdoc opt">(</span><span class="function"><a href="/usr/share/gtk-doc/html/gstreamer-1.0/GstMessage.html#GST-MESSAGE-TYPE:CAPS">GST_MESSAGE_TYPE</a></span> <span class="gtkdoc opt">(</span>message<span class="gtkdoc opt">)) {</span>
    <span class="keyword">case</span> GST_MESSAGE_ERROR<span class="gtkdoc opt">:</span>
      <span class="function"><a href="/usr/share/gtk-doc/html/glib/glib-Message-Logging.html#g-error">g_error</a></span> <span class="gtkdoc opt">(</span><span class="string">&quot;Got ERROR&quot;</span><span class="gtkdoc opt">);</span>
      <span class="function"><a href="/usr/share/gtk-doc/html/glib/glib-The-Main-Event-Loop.html#g-main-loop-quit">g_main_loop_quit</a></span> <span class="gtkdoc opt">(</span>loop<span class="gtkdoc opt">);</span>
      <span class="keyword">break</span><span class="gtkdoc opt">;</span>
    <span class="keyword">case</span> GST_MESSAGE_WARNING<span class="gtkdoc opt">:</span>
      <span class="function"><a href="/usr/share/gtk-doc/html/glib/glib-Message-Logging.html#g-warning">g_warning</a></span> <span class="gtkdoc opt">(</span><span class="string">&quot;Got WARNING&quot;</span><span class="gtkdoc opt">);</span>
      <span class="function"><a href="/usr/share/gtk-doc/html/glib/glib-The-Main-Event-Loop.html#g-main-loop-quit">g_main_loop_quit</a></span> <span class="gtkdoc opt">(</span>loop<span class="gtkdoc opt">);</span>
      <span class="keyword">break</span><span class="gtkdoc opt">;</span>
    <span class="keyword">case</span> GST_MESSAGE_EOS<span class="gtkdoc opt">:</span>
      <span class="function"><a href="/usr/share/gtk-doc/html/glib/glib-The-Main-Event-Loop.html#g-main-loop-quit">g_main_loop_quit</a></span> <span class="gtkdoc opt">(</span>loop<span class="gtkdoc opt">);</span>
      <span class="keyword">break</span><span class="gtkdoc opt">;</span>
    <span class="keyword">default</span><span class="gtkdoc opt">:</span>
      <span class="keyword">break</span><span class="gtkdoc opt">;</span>
  <span class="gtkdoc opt">}</span>

  <span class="keyword">return</span> TRUE<span class="gtkdoc opt">;</span>
<span class="gtkdoc opt">}</span>

<span class="gtkdoc kwb">static void</span>
<span class="function">on_rate_changed</span> <span class="gtkdoc opt">(</span>GstElement <span class="gtkdoc opt">*</span> element<span class="gtkdoc opt">,</span> gint rate<span class="gtkdoc opt">,</span> gpointer user_data<span class="gtkdoc opt">)</span>
<span class="gtkdoc opt">{</span>
  GValueArray <span class="gtkdoc opt">*</span>va<span class="gtkdoc opt">;</span>
  GValue v <span class="gtkdoc opt">= {</span> <span class="number">0</span><span class="gtkdoc opt">, };</span>
  gdouble x<span class="gtkdoc opt">;</span>

  <span class="keyword">if</span> <span class="gtkdoc opt">(</span>rate <span class="gtkdoc opt">/</span> <span class="number">2.0</span> <span class="gtkdoc opt">&gt;</span> CUTOFF<span class="gtkdoc opt">)</span>
    x <span class="gtkdoc opt">=</span> <span class="function">exp</span> <span class="gtkdoc opt">(-</span><span class="number">2.0</span> <span class="gtkdoc opt">*</span> G_PI <span class="gtkdoc opt">* (</span>CUTOFF <span class="gtkdoc opt">/</span> rate<span class="gtkdoc opt">));</span>
  <span class="keyword">else</span>
    x <span class="gtkdoc opt">=</span> <span class="number">0.0</span><span class="gtkdoc opt">;</span>

  va <span class="gtkdoc opt">=</span> <span class="function"><a href="/usr/share/gtk-doc/html/gobject/gobject-Value-arrays.html#g-value-array-new">g_value_array_new</a></span> <span class="gtkdoc opt">(</span><span class="number">1</span><span class="gtkdoc opt">);</span>

  <span class="function"><a href="/usr/share/gtk-doc/html/gobject/gobject-Generic-values.html#g-value-init">g_value_init</a></span> <span class="gtkdoc opt">(&amp;</span>v<span class="gtkdoc opt">,</span> G_TYPE_DOUBLE<span class="gtkdoc opt">);</span>
  <span class="function"><a href="/usr/share/gtk-doc/html/gobject/gobject-Standard-Parameter-and-Value-Types.html#g-value-set-double">g_value_set_double</a></span> <span class="gtkdoc opt">(&amp;</span>v<span class="gtkdoc opt">,</span> <span class="number">1.0</span> <span class="gtkdoc opt">-</span> x<span class="gtkdoc opt">);</span>
  <span class="function"><a href="/usr/share/gtk-doc/html/gobject/gobject-Value-arrays.html#g-value-array-append">g_value_array_append</a></span> <span class="gtkdoc opt">(</span>va<span class="gtkdoc opt">, &amp;</span>v<span class="gtkdoc opt">);</span>
  <span class="function"><a href="/usr/share/gtk-doc/html/gobject/gobject-Generic-values.html#g-value-reset">g_value_reset</a></span> <span class="gtkdoc opt">(&amp;</span>v<span class="gtkdoc opt">);</span>
  <span class="function"><a href="/usr/share/gtk-doc/html/gobject/gobject-The-Base-Object-Type.html#g-object-set">g_object_set</a></span> <span class="gtkdoc opt">(</span><span class="function"><a href="/usr/share/gtk-doc/html/gobject/gobject-The-Base-Object-Type.html#G-OBJECT:CAPS">G_OBJECT</a></span> <span class="gtkdoc opt">(</span>element<span class="gtkdoc opt">),</span> <span class="string">&quot;a&quot;</span><span class="gtkdoc opt">,</span> va<span class="gtkdoc opt">,</span> NULL<span class="gtkdoc opt">);</span>
  <span class="function"><a href="/usr/share/gtk-doc/html/gobject/gobject-Value-arrays.html#g-value-array-free">g_value_array_free</a></span> <span class="gtkdoc opt">(</span>va<span class="gtkdoc opt">);</span>

  va <span class="gtkdoc opt">=</span> <span class="function"><a href="/usr/share/gtk-doc/html/gobject/gobject-Value-arrays.html#g-value-array-new">g_value_array_new</a></span> <span class="gtkdoc opt">(</span><span class="number">1</span><span class="gtkdoc opt">);</span>
  <span class="function"><a href="/usr/share/gtk-doc/html/gobject/gobject-Standard-Parameter-and-Value-Types.html#g-value-set-double">g_value_set_double</a></span> <span class="gtkdoc opt">(&amp;</span>v<span class="gtkdoc opt">,</span> x<span class="gtkdoc opt">);</span>
  <span class="function"><a href="/usr/share/gtk-doc/html/gobject/gobject-Value-arrays.html#g-value-array-append">g_value_array_append</a></span> <span class="gtkdoc opt">(</span>va<span class="gtkdoc opt">, &amp;</span>v<span class="gtkdoc opt">);</span>
  <span class="function"><a href="/usr/share/gtk-doc/html/gobject/gobject-Generic-values.html#g-value-reset">g_value_reset</a></span> <span class="gtkdoc opt">(&amp;</span>v<span class="gtkdoc opt">);</span>
  <span class="function"><a href="/usr/share/gtk-doc/html/gobject/gobject-The-Base-Object-Type.html#g-object-set">g_object_set</a></span> <span class="gtkdoc opt">(</span><span class="function"><a href="/usr/share/gtk-doc/html/gobject/gobject-The-Base-Object-Type.html#G-OBJECT:CAPS">G_OBJECT</a></span> <span class="gtkdoc opt">(</span>element<span class="gtkdoc opt">),</span> <span class="string">&quot;b&quot;</span><span class="gtkdoc opt">,</span> va<span class="gtkdoc opt">,</span> NULL<span class="gtkdoc opt">);</span>
  <span class="function"><a href="/usr/share/gtk-doc/html/gobject/gobject-Value-arrays.html#g-value-array-free">g_value_array_free</a></span> <span class="gtkdoc opt">(</span>va<span class="gtkdoc opt">);</span>
<span class="gtkdoc opt">}</span>

gint
<span class="function">main</span> <span class="gtkdoc opt">(</span>gint argc<span class="gtkdoc opt">,</span> gchar <span class="gtkdoc opt">*</span> argv<span class="gtkdoc opt">[])</span>
<span class="gtkdoc opt">{</span>
  GstElement <span class="gtkdoc opt">*</span>pipeline<span class="gtkdoc opt">, *</span>src<span class="gtkdoc opt">, *</span>filter<span class="gtkdoc opt">, *</span>conv<span class="gtkdoc opt">, *</span>sink<span class="gtkdoc opt">;</span>
  GstBus <span class="gtkdoc opt">*</span>bus<span class="gtkdoc opt">;</span>
  GMainLoop <span class="gtkdoc opt">*</span>loop<span class="gtkdoc opt">;</span>

  <span class="function"><a href="/usr/share/gtk-doc/html/gstreamer-1.0/gstreamer-Gst.html#gst-init">gst_init</a></span> <span class="gtkdoc opt">(</span>NULL<span class="gtkdoc opt">,</span> NULL<span class="gtkdoc opt">);</span>

  pipeline <span class="gtkdoc opt">=</span> <span class="function"><a href="/usr/share/gtk-doc/html/gstreamer-1.0/GstElementFactory.html#gst-element-factory-make">gst_element_factory_make</a></span> <span class="gtkdoc opt">(</span><span class="string">&quot;pipeline&quot;</span><span class="gtkdoc opt">,</span> NULL<span class="gtkdoc opt">);</span>

  src <span class="gtkdoc opt">=</span> <span class="function"><a href="/usr/share/gtk-doc/html/gstreamer-1.0/GstElementFactory.html#gst-element-factory-make">gst_element_factory_make</a></span> <span class="gtkdoc opt">(</span><span class="string">&quot;audiotestsrc&quot;</span><span class="gtkdoc opt">,</span> NULL<span class="gtkdoc opt">);</span>
  <span class="function"><a href="/usr/share/gtk-doc/html/gobject/gobject-The-Base-Object-Type.html#g-object-set">g_object_set</a></span> <span class="gtkdoc opt">(</span><span class="function"><a href="/usr/share/gtk-doc/html/gobject/gobject-The-Base-Object-Type.html#G-OBJECT:CAPS">G_OBJECT</a></span> <span class="gtkdoc opt">(</span>src<span class="gtkdoc opt">),</span> <span class="string">&quot;wave&quot;</span><span class="gtkdoc opt">,</span> <span class="number">5</span><span class="gtkdoc opt">,</span> NULL<span class="gtkdoc opt">);</span>

  filter <span class="gtkdoc opt">=</span> <span class="function"><a href="/usr/share/gtk-doc/html/gstreamer-1.0/GstElementFactory.html#gst-element-factory-make">gst_element_factory_make</a></span> <span class="gtkdoc opt">(</span><span class="string">&quot;audioiirfilter&quot;</span><span class="gtkdoc opt">,</span> NULL<span class="gtkdoc opt">);</span>
  <span class="function"><a href="/usr/share/gtk-doc/html/gobject/gobject-Signals.html#g-signal-connect">g_signal_connect</a></span> <span class="gtkdoc opt">(</span><span class="function"><a href="/usr/share/gtk-doc/html/gobject/gobject-The-Base-Object-Type.html#G-OBJECT:CAPS">G_OBJECT</a></span> <span class="gtkdoc opt">(</span>filter<span class="gtkdoc opt">),</span> <span class="string">&quot;rate-changed&quot;</span><span class="gtkdoc opt">,</span>
      <span class="function"><a href="/usr/share/gtk-doc/html/gobject/gobject-Closures.html#G-CALLBACK:CAPS">G_CALLBACK</a></span> <span class="gtkdoc opt">(</span>on_rate_changed<span class="gtkdoc opt">),</span> NULL<span class="gtkdoc opt">);</span>

  conv <span class="gtkdoc opt">=</span> <span class="function"><a href="/usr/share/gtk-doc/html/gstreamer-1.0/GstElementFactory.html#gst-element-factory-make">gst_element_factory_make</a></span> <span class="gtkdoc opt">(</span><span class="string">&quot;audioconvert&quot;</span><span class="gtkdoc opt">,</span> NULL<span class="gtkdoc opt">);</span>

  sink <span class="gtkdoc opt">=</span> <span class="function"><a href="/usr/share/gtk-doc/html/gstreamer-1.0/GstElementFactory.html#gst-element-factory-make">gst_element_factory_make</a></span> <span class="gtkdoc opt">(</span><span class="string">&quot;autoaudiosink&quot;</span><span class="gtkdoc opt">,</span> NULL<span class="gtkdoc opt">);</span>
  <span class="function"><a href="/usr/share/gtk-doc/html/glib/glib-Warnings-and-Assertions.html#g-return-val-if-fail">g_return_val_if_fail</a></span> <span class="gtkdoc opt">(</span>sink <span class="gtkdoc opt">!=</span> NULL<span class="gtkdoc opt">, -</span><span class="number">1</span><span class="gtkdoc opt">);</span>

  <span class="function"><a href="/usr/share/gtk-doc/html/gstreamer-1.0/GstBin.html#gst-bin-add-many">gst_bin_add_many</a></span> <span class="gtkdoc opt">(</span><span class="function">GST_BIN</span> <span class="gtkdoc opt">(</span>pipeline<span class="gtkdoc opt">),</span> src<span class="gtkdoc opt">,</span> filter<span class="gtkdoc opt">,</span> conv<span class="gtkdoc opt">,</span> sink<span class="gtkdoc opt">,</span> NULL<span class="gtkdoc opt">);</span>
  <span class="keyword">if</span> <span class="gtkdoc opt">(!</span><span class="function"><a href="/usr/share/gtk-doc/html/gstreamer-1.0/GstElement.html#gst-element-link-many">gst_element_link_many</a></span> <span class="gtkdoc opt">(</span>src<span class="gtkdoc opt">,</span> filter<span class="gtkdoc opt">,</span> conv<span class="gtkdoc opt">,</span> sink<span class="gtkdoc opt">,</span> NULL<span class="gtkdoc opt">)) {</span>
    <span class="function"><a href="/usr/share/gtk-doc/html/glib/glib-Message-Logging.html#g-error">g_error</a></span> <span class="gtkdoc opt">(</span><span class="string">&quot;Failed to link elements&quot;</span><span class="gtkdoc opt">);</span>
    <span class="keyword">return</span> <span class="gtkdoc opt">-</span><span class="number">2</span><span class="gtkdoc opt">;</span>
  <span class="gtkdoc opt">}</span>

  loop <span class="gtkdoc opt">=</span> <span class="function"><a href="/usr/share/gtk-doc/html/glib/glib-The-Main-Event-Loop.html#g-main-loop-new">g_main_loop_new</a></span> <span class="gtkdoc opt">(</span>NULL<span class="gtkdoc opt">,</span> FALSE<span class="gtkdoc opt">);</span>

  bus <span class="gtkdoc opt">=</span> <span class="function"><a href="/usr/share/gtk-doc/html/gstreamer-1.0/GstPipeline.html#gst-pipeline-get-bus">gst_pipeline_get_bus</a></span> <span class="gtkdoc opt">(</span><span class="function">GST_PIPELINE</span> <span class="gtkdoc opt">(</span>pipeline<span class="gtkdoc opt">));</span>
  <span class="function"><a href="/usr/share/gtk-doc/html/gstreamer-1.0/GstBus.html#gst-bus-add-signal-watch">gst_bus_add_signal_watch</a></span> <span class="gtkdoc opt">(</span>bus<span class="gtkdoc opt">);</span>
  <span class="function"><a href="/usr/share/gtk-doc/html/gobject/gobject-Signals.html#g-signal-connect">g_signal_connect</a></span> <span class="gtkdoc opt">(</span><span class="function"><a href="/usr/share/gtk-doc/html/gobject/gobject-The-Base-Object-Type.html#G-OBJECT:CAPS">G_OBJECT</a></span> <span class="gtkdoc opt">(</span>bus<span class="gtkdoc opt">),</span> <span class="string">&quot;message&quot;</span><span class="gtkdoc opt">,</span> <span class="function"><a href="/usr/share/gtk-doc/html/gobject/gobject-Closures.html#G-CALLBACK:CAPS">G_CALLBACK</a></span> <span class="gtkdoc opt">(</span>on_message<span class="gtkdoc opt">),</span> loop<span class="gtkdoc opt">);</span>
  <span class="function"><a href="/usr/share/gtk-doc/html/gstreamer-1.0/GstObject.html#gst-object-unref">gst_object_unref</a></span> <span class="gtkdoc opt">(</span><span class="function">GST_OBJECT</span> <span class="gtkdoc opt">(</span>bus<span class="gtkdoc opt">));</span>

  <span class="keyword">if</span> <span class="gtkdoc opt">(</span><span class="function"><a href="/usr/share/gtk-doc/html/gstreamer-1.0/GstElement.html#gst-element-set-state">gst_element_set_state</a></span> <span class="gtkdoc opt">(</span>pipeline<span class="gtkdoc opt">,</span>
          GST_STATE_PLAYING<span class="gtkdoc opt">) ==</span> GST_STATE_CHANGE_FAILURE<span class="gtkdoc opt">) {</span>
    <span class="function"><a href="/usr/share/gtk-doc/html/glib/glib-Message-Logging.html#g-error">g_error</a></span> <span class="gtkdoc opt">(</span><span class="string">&quot;Failed to go into PLAYING state&quot;</span><span class="gtkdoc opt">);</span>
    <span class="keyword">return</span> <span class="gtkdoc opt">-</span><span class="number">3</span><span class="gtkdoc opt">;</span>
  <span class="gtkdoc opt">}</span>

  <span class="function"><a href="/usr/share/gtk-doc/html/glib/glib-The-Main-Event-Loop.html#g-main-loop-run">g_main_loop_run</a></span> <span class="gtkdoc opt">(</span>loop<span class="gtkdoc opt">);</span>

  <span class="function"><a href="/usr/share/gtk-doc/html/gstreamer-1.0/GstElement.html#gst-element-set-state">gst_element_set_state</a></span> <span class="gtkdoc opt">(</span>pipeline<span class="gtkdoc opt">,</span> GST_STATE_NULL<span class="gtkdoc opt">);</span>

  <span class="function"><a href="/usr/share/gtk-doc/html/glib/glib-The-Main-Event-Loop.html#g-main-loop-unref">g_main_loop_unref</a></span> <span class="gtkdoc opt">(</span>loop<span class="gtkdoc opt">);</span>
  <span class="function"><a href="/usr/share/gtk-doc/html/gstreamer-1.0/GstObject.html#gst-object-unref">gst_object_unref</a></span> <span class="gtkdoc opt">(</span>pipeline<span class="gtkdoc opt">);</span>

  <span class="keyword">return</span> <span class="number">0</span><span class="gtkdoc opt">;</span>
<span class="gtkdoc opt">}</span></pre></td>
      </tr>
    </tbody>
  </table>
</div>

</div>
<div class="refsynopsisdiv">
<h2>Synopsis</h2>
<div class="refsect2">
<a name="id-1.2.22.8.6.1"></a><h3>Element Information</h3>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term">plugin</span></p></td>
<td>
            <a class="link" href="gst-plugins-good-plugins-plugin-audiofx.html#plugin-audiofx">audiofx</a>
          </td>
</tr>
<tr>
<td><p><span class="term">author</span></p></td>
<td>Sebastian Dröge &lt;sebastian.droege@collabora.co.uk&gt;</td>
</tr>
<tr>
<td><p><span class="term">class</span></p></td>
<td>Filter/Effect/Audio</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2">
<a name="id-1.2.22.8.6.2"></a><h3>Element Pads</h3>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term">name</span></p></td>
<td>sink</td>
</tr>
<tr>
<td><p><span class="term">direction</span></p></td>
<td>sink</td>
</tr>
<tr>
<td><p><span class="term">presence</span></p></td>
<td>always</td>
</tr>
<tr>
<td><p><span class="term">details</span></p></td>
<td>audio/x-raw, format=(string){ F32LE, F64LE }, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ], layout=(string)interleaved</td>
</tr>
</tbody>
</table></div>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term">name</span></p></td>
<td>src</td>
</tr>
<tr>
<td><p><span class="term">direction</span></p></td>
<td>source</td>
</tr>
<tr>
<td><p><span class="term">presence</span></p></td>
<td>always</td>
</tr>
<tr>
<td><p><span class="term">details</span></p></td>
<td>audio/x-raw, format=(string){ F32LE, F64LE }, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ], layout=(string)interleaved</td>
</tr>
</tbody>
</table></div>
</div>
</div>
</div>
<div class="refsect1">
<a name="gst-plugins-good-plugins-audioiirfilter.functions_details"></a><h2>Functions</h2>
<p></p>
</div>
<div class="refsect1">
<a name="gst-plugins-good-plugins-audioiirfilter.other_details"></a><h2>Types and Values</h2>
<div class="refsect2">
<a name="GstAudioIIRFilter-struct"></a><h3>struct GstAudioIIRFilter</h3>
<pre class="programlisting">struct GstAudioIIRFilter;</pre>
<p>Opaque data structure.</p>
</div>
</div>
<div class="refsect1">
<a name="gst-plugins-good-plugins-audioiirfilter.property-details"></a><h2>Property Details</h2>
<div class="refsect2">
<a name="GstAudioIIRFilter--a"></a><h3>The <code class="literal">“a”</code> property</h3>
<pre class="programlisting">  “a”                        <a href="/usr/share/gtk-doc/html/gobject/gobject-Value-arrays.html#GValueArray-struct"><span class="type">GValueArray</span></a> *</pre>
<p>Filter coefficients (denominator of transfer function).</p>
<p>Flags: Read / Write</p>
</div>
<hr>
<div class="refsect2">
<a name="GstAudioIIRFilter--b"></a><h3>The <code class="literal">“b”</code> property</h3>
<pre class="programlisting">  “b”                        <a href="/usr/share/gtk-doc/html/gobject/gobject-Value-arrays.html#GValueArray-struct"><span class="type">GValueArray</span></a> *</pre>
<p>Filter coefficients (numerator of transfer function).</p>
<p>Flags: Read / Write</p>
</div>
</div>
<div class="refsect1">
<a name="gst-plugins-good-plugins-audioiirfilter.signal-details"></a><h2>Signal Details</h2>
<div class="refsect2">
<a name="GstAudioIIRFilter-rate-changed"></a><h3>The <code class="literal">“rate-changed”</code> signal</h3>
<pre class="programlisting"><span class="returnvalue">void</span>
user_function (<a class="link" href="gst-plugins-good-plugins-audioiirfilter.html#GstAudioIIRFilter"><span class="type">GstAudioIIRFilter</span></a> *filter,
               <a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gint"><span class="type">gint</span></a>               rate,
               <a href="/usr/share/gtk-doc/html/glib/glib-Basic-Types.html#gpointer"><span class="type">gpointer</span></a>           user_data)</pre>
<p>Will be emitted when the sampling rate changes. The callbacks
will be called from the streaming thread and processing will
stop until the event is handled.</p>
<div class="refsect3">
<a name="GstAudioIIRFilter-rate-changed.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody>
<tr>
<td class="parameter_name"><p>filter</p></td>
<td class="parameter_description"><p>the filter on which the signal is emitted</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>rate</p></td>
<td class="parameter_description"><p>the new sampling rate</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>user_data</p></td>
<td class="parameter_description"><p>user data set when the signal handler was connected.</p></td>
<td class="parameter_annotations"> </td>
</tr>
</tbody>
</table></div>
</div>
<p>Flags: <a href="/usr/share/gtk-doc/html/gobject/gobject-Signals.html#G-SIGNAL-RUN-LAST:CAPS">Run Last</a></p>
</div>
</div>
</div>
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